Device with a circular blade for cutting flat marble, granite and glass sheets

ABSTRACT

A circular blade device ( 1 ) for cutting flat marble, granite, glass or similar sheets ( 5 ), including numerical control elements ( 2 ) for a cutting head ( 3 ) having a blade ( 14 ) addressable within a cutting volume, which includes elements for manipulating the sheets within the cutting volume.

The present invention relates to a circular blade device for cuttingflat marble, granite and glass sheets, in accordance with theintroduction to the main claim.

Sheet cutting devices have been available commercially for some time,devices provided with a diamond-set circular blade being habitually usedfor cutting marble, granite, general stone, glass and other sheets.

The blade is usually controlled by numerical control means, which guideit during sheet cutting. Such sheets present virtually standarddimensions, and need to be shaped to form table tops, steps for stairs,kitchen worktops, etc. The sheets are cut by laying them on a cuttingarea and operating the cutting device.

However, as is well known to the expert of the art, the use ofdiamond-set circular blades does not enable a cut to be made withoutmaterial wastage. In this respect because of its particular shape, theblade cuts completely only on its diagonal to the cutting plane while,depending on the blade radius, the material present more or less distantfrom the diagonal is only partly cut. In effect the shape of the cutfollows the shape of the blade.

When cutting stone sheets, in most cases a first series of longitudinalcuts are made along the entire length of the sheet. The sheets are thenmoved manually and the transverse cuts are made. This manual movement isdone by expert operators such as to exclude the sheet appendices fromthe range of action of the blade, to hence enable the transverse cut tobe made without damaging the previously worked sheets. However thisoperation requires the presence of an operator to continuously supervisethe production process. Moreover the idle times due to this movement areextremely harmful to machine productivity. In this respect, theadvantage of a numerically controlled working centre is not only itsworking precision but also its high productivity; the presence of suchidle times leads to a halving of the rated productivity of the machine,plus a reduction in precision due to the manual positioning.

In addition, granite, glass and the like present a considerableresistance to compression, but a very poor resistance to tension andconsequently to bending. This means that those sheets presenting partswith a small resistant cross-section have to be reinforced by means ofan insert of rigid material (steel or the like) glued into one or morelongitudinal grooves made in said cross-section. Sheets presenting smallsections or unconventional shapes also often require reinforcements. Thegrooves for housing the reinforcements are evidently made in the lowerside of the sheet given that the upper side, which is the visible andhence finished side, must not present imperfections.

Currently, these grooves are usually made by using conventional sheetcutting machines; the sheet is turned over, rested on the cuttingsupport with its face downwards, and the grooves made by the samecircular blade as used for cutting the sheet. Afterwards, when thereinforcements have been positioned and glued in, the notches are madewhich reduce the resistant cross-section.

This is extremely uncomfortable and dangerous. In effect the uppersurface of the sheets is substantially finished before proceeding to thesheet cutting; however in making the groove or grooves the sheet isplaced with its finished surface on the cutting support. This can causescraping or scoring of the finished surface of the sheet, making furtherfinishing necessary, with considerable increase in final product costand with negative consequences regarding productivity.

Moreover when the sheet is turned over, it may break precisely alongthose sections of least resistance.

An object of the present invention is therefore to provide a circularblade device for cutting flat marble, granite and glass sheets whicheliminates the stated technical drawbacks of the known art.

A further object of the present invention is in particular to provide acircular blade device for cutting flat marble, granite and glass sheetswhich eliminates those idle times which arise from the need to manuallymove the cut sheets in order to make new cuts.

A further object of the invention is to eliminate or at least reducemanual operations during a working cycle of the said cutting device inorder to improve working precision.

A further object of the invention is to provide a circular blade devicefor cutting flat sheets which enables the grooves to be made in thelower side of the sheet without having to turn it over or rest it on thefinished side for support, hence avoiding the danger of scraping orscoring the finished surface, or of breaking the sheet.

These and further objects are attained by a circular blade device forcutting flat marble, granite, glass and similar sheets in accordancewith the accompanying claims.

Further characteristics and advantages will be more apparent from thedescription of a preferred but non-exclusive embodiment of the circularblade device for cutting flat sheets according to the invention,illustrated by way of non-limiting example in the accompanying drawings,in which:

FIG. 1 is a front view of the circular blade device for cutting flatsheets according to the present invention;

FIG. 2 is a plan view of the device of FIG. 1;

FIG. 3 is a front view of a different embodiment of the device of thepresent invention;

FIG. 4 is a plan view of the device of FIG. 3;

FIG. 5 is an enlarged view of a detail of the device of FIG. 3;

FIG. 6 is a view of a different embodiment of the detail of FIG. 5;

FIG. 7 is a plan view of the operating stages of the device of FIG. 1;

Figures from 8 to 10 are side views showing operating stages of thedevice of FIG. 3;

FIG. 11 is a partly sectional schematic side view of a differentembodiment of the device of FIG. 1, in which an additional part is shownlateral to the cutting plane of FIG. 1;

Figures from 12 to 17 show various positioning and cutting stages of thesheet on the device shown in detail in FIG. 9; and

FIGS. 18 and 19 show sheets formed by the additional part of FIG. 11.

Said figures show a circular blade device for cutting flat marble,granite, glass and similar sheets, indicated overall by the numeral 1.

The device comprises a numerical control unit 2 of known type,controlling a cutting head 3 addressable within a cutting volume 4. Thecutting head 3, by virtue of manipulating means to which it is connected(and described hereinafter), and addressed by the numerical control unit2, can reach any point of this volume and, in particular, can reach anypoint of a flat sheet 5, resting on a cutting support 6. The support 6comprises in known manner a plurality of rollers 6K on which the sheet 5rests.

Said manipulating means enable the cutting head 3 to be moved along ahorizontal first axis of translation 7 perpendicular to a second 8,these being perpendicular to a vertical third axis of translation of thecutting head 3.

The movement along said axes is obtained by moving a support 3A for thecutting head 3 along a plate or arm 8A lying along the axis 8. Thisplate or arm 8A can be moved, by usual electrical actuators (not shown),along parallel arms 7A positioned in correspondence with opposing sides6A of the cutting support 6 and hence lying along the axis 7. The plateor arm 8A moves along the arms 7A rigidly with the support 3A for thecutting head. This support also slides along a guide 9A positioned alongthe axis 9 to enable the support 3A to move therealong. This sliding isachieved by a suitable electrical actuator, not shown.

The support 3A contains usual means for moving the cutting head, asdescribed hereinafter.

The position control for the head 3, effected along these axes, enablesthe head to reach any position of the sheet, along any trajectory. Thenumerical control unit 2 also controls the head movements about anothertwo axes, i.e. rotation about the axis 9 to enable cuts such as thatshown in FIG. 2 (i.e. diagonal cuts) to be made, and rotation about anaxis 10 perpendicular to the axis 9 (FIG. 1) to enable cuts to be madewith their edge inclined to the upper and lower surface of the sheet.

An articulated arm 17 constitutes a means for moving the sheetappendices 5 a, 5 b, 5 c, 5 d, 5 e, 5 f cut by a diamond-set circularblade 14 present on the cutting head 3. This articulated arm comprises afirst straight part 17A which carries a slider 13 (movable along thatpart) and is perpendicular to and movable relative to a fixed secondstraight part 17B. The slider 13 presents vertically mobile manipulatormembers 12, which in the case of FIG. 1 are of sucker form. Thesemembers 12, in combination with the movements of the slider 13 of theentire articulated arm 17, enable any of the cut sheet portions 5 a-5 fto be transported into any point of the cutting region, and inparticular out of the range of action of the blade 14. The first part17A is driven, under the control of the unit 2, by usual electricalactuators, not shown.

In a different embodiment, the means for moving said sheets comprise thecutting head 3, equipped with sucker members 12.

The movable members 12 are controlled in their vertical movement byactuator means, which in this particular example, and as visible in FIG.5, are pneumatic pistons rigid with the cutting head 3. This lattercomprises a usual electric motor 30 the shaft 31 of which carries theblade 14.

The operation of the aforedescribed device is apparent from thatillustrated: in this respect the cutting head 3, and in particular itsmanipulation system comprising the numerical control unit and theelements movable along the perpendicular axes 7, 8, 9, accomplishes thedouble purpose of supporting and addressing the blade 14 in its cuttingmotion, and of manipulating the sheet 5 and its portions 5 a-5 f.

In FIGS. 7 and 8 the operation of the cutting device is shown in itsvarious stages. In stage A of FIG. 7, the sheet is in one piece and hasjust been rested on the support 6. The blade then operates to make cuts50, 51 which divide the sheet into three parts 52, 53 and 54 (stage B ofFIG. 7). The manipulation system is positioned above the sheet portionto be moved, and in this case above the portion 54 (FIG. 8, stage F); itcan be seen that in this case the sucker members 12 are higher than thelower edge of the blade, to enable the cut to be made. Then, without thecutting head 3 changing position, the pneumatic piston 15 is operated tolower the sucker members 12 onto the sheet, and grip it (stage C of FIG.7 and stage G of FIG. 8). The cutting head 3 is raised a fewmillimetres, sufficient to detach the sheet, locked by the suckers, fromthe support 6 (stage H of FIG. 8). The head 3 is then moved sideways(stage D of FIG. 7), lowered and the sucker members 12 removed from thesheet. The necessary transverse cuts 55 are then made.

In a different embodiment shown in FIG. 6, the manipulator members 12are wedges which are inserted into the gap left by the cut between thecutting edges; in this case, when the head 3 undergoes a transversemovement (without raising), the cut sheet portion moves. Hence, ontermination of the cut, the head 3 is positioned such that the wedgeslie above the cut (FIG. 9, stage 1). The wedge is then lowered into theinterior of the cut, until it at least partly penetrates it (FIG. 9,stage L). The head 3 is moved transversely with the wedges lowered, withthe result that the sheet is removed from the others by sliding alongthe support. The cut 55 is then made, as in the preceding cases.

In a further embodiment, it is the blade itself which, on termination ofits cutting movement, is used as the appendix for moving the sheetportions, by operating along the edges of the cut.

In that case, on termination of the cut the head 3 remains inside thecut (FIG. 10, stage N) and is then moved laterally to consequently movethe sheet, which slides along the support 6. The transverse cut or cuts55 are then made as previously.

In a different embodiment, the manipulator members 12, and in particularthe suckers, are addressed in such a manner as to enable them to movewithin a cutting volume 4 which is much larger than that shown in FIG.1; in particular this volume 4 extends well beyond the cutting support6.

To the side of said support 6 a ledge 60 is present (see FIG. 11) fixedto said support by screws 61. Present on said ledge 60 there arevertical guides 62 on which a frame 63 is present, supporting a millingmachine 64 provided with a cutting disc 65. The frame 63 is movedvertically by an actuator 66, for example of pressurized fluid type,which is fixed to the ledge (at 67) and to the frame (at 68) to controlthe vertical movement of the milling machine 64.

Hence the milling machine is disposed substantially to the side of thecutting support and below the surface on which the sheet rests, andcarries a cutting disc 65 able to be brought into a position higher thanthe cutting support 6.

This embodiment operates in the following manner:

when the sheet has been cut by the cutting head 3 (FIG. 12) in themanner already explained, the sheet 5′ is raised (FIG. 13) andpositioned above the milling machine 64 (FIG. 14).

The sheet 5 is raised substantially by the suction members 12, whetherthese are mobilized by the cutting head 3 or by an independent slider13. It should be noted that in Figures from 12 to 17, mobilization isobtained by the slider 13, however it can be equally obtained by meansof the cutting head 3, as already described.

Moreover, the sheet 5 does not necessarily have to be raised to bebrought above the blade, but can advantageously be slid along thesupport 6 by the already described manipulation systems.

The actuator 66 (which in the illustrated example is of the pressurizedfluid type) then raises the milling machine 64 which makes the cut inthe lower surface of the sheet 5.

The cutting movement is imposed by the movement of the slider 13 (thismovement in FIG. 5 being substantially perpendicular to the plane of thedrawing). Hence the groove 70 is obtained in practice.

The milling machine 64 is then lowered (FIG. 16) and the sheet 5 ismoved to make a second groove 71, in the same manner as the first.

This is evidently a description of only one of the numerous cuttingcycles obtainable by such a device.

In particular a cutting device such as that described is alsoadvantageous in making grooves in the lower surface of already finishedsheets 5, such as that of FIGS. 18 and 19; in this respect the uppersurface comes into contact only with the suckers 12, so avoidingsituations which could ruin it.

In a different embodiment the milling machine 64 is mounted on arotatable platform (not shown but totally conventional), which enablesthe cutting plane of the blade to be rotated through at least 90°, sothat the groove can also be made in a direction, for example,perpendicular to that of the grooves 70 and 71.

A circular blade device for cutting flat marble, granite and glasssheets conceived in this manner is susceptible to numerous modificationsand variants, all falling within the scope of the inventive concept;moreover all details can be replaced by technically equivalent elements.

In practice the materials used and the shapes and dimensions can bechosen at will according to requirements and to the state of the art.

1-18. (canceled)
 19. A circular blade device (1) for cutting flatmarble, granite, glass or similar sheets (5), comprising numericalcontrol means (2) for a cutting head (3) having a blade (14) addressablewithin a cutting volume and comprising means for manipulating saidsheets within said cutting volume, characterised in that themanipulating means for said sheets (5) comprise at least one manipulatormember (12) extending from the cutting head (3), said manipulator memberbeing arranged to cooperate with the sheet being cut and comprisingsuckers.
 20. A device as claimed in claim 19, characterised in that saidmanipulator member is associated with actuator means (15) which enableit to move vertically.
 21. A device as claimed in claim 20,characterised in that said actuator means (15) are rigid with thecutting head (3).
 22. A device as claimed in claim 20, characterized inthat said actuator means (15) are of pneumatic type.
 23. A device asclaimed in claim 20, characterised in that the numerical control-means(2) control said actuators.
 24. A device as claimed in claim 19,characterised in that the suckers operate on the surface of the sheets.25. A device as claimed in claim 19, characterized in that numericalcontrol means (2) are arranged to move the cutting head (13) along afirst, a second and a third axis (7, 8, 9) of translation perpendicularto one another and, moreover, arranged to rotate said cutting head (3)about said third axis (9) to allow diagonal cuts to be made.
 26. Adevice as claimed in claim 25, characterized in that said numericalcontrol means (2) are arranged to rotate said cutting head (3) about afourth axis (10) perpendicular to said third axis (9), to enable cuts tobe made with their edge inclined to the upper and lower surface of thesheet.
 27. A device as claimed in claim 19, characterized by presentinga cutting disc (65) disposed below the sheets (5) in such a manner as tooperate on the lower face of the sheets (5).
 28. A device as claimed inclaim 25, characterised in that said cutting disc (56) is disposed tothe side of a cutting support (6) on which said sheet (5) is restedduring the cutting by the cutting head.
 29. A device as claimed in claim25, characterised in that said cutting disc (65) can be moved verticallyby one or more actuators (66).
 30. A device as claimed in claim 25,characterised in that said cutting disc (65) forms part of a millingmachine (64) rigid both with a frame (63) mounted on vertical guides(62) and with an actuator (66) for vertically moving said disc (65). 31.A device as claimed in claim 30, characterised in that said verticalguides (62) are fixed to a ledge (60) projecting from said support (6).32. A device as claimed in claim 25, characterised in that said cuttingdisc (65) can be moved about a vertical axis of rotation to vary itscutting direction.